Density-functional study of the electronic and optical properties of the spinel compound CuIr₂S₄

Abstract

Using first-principles density-functional calculations we have computed the electronic and optical properties of spinel compound CuIr₂S₄, which undergoes a structural phase transition, accompanied by a metal-insulator transition at a temperature of about 230 K. The nature of this transition has been discussed in the literature in terms of both the correlated singlet formation picture as well as the orbitally driven Peierls transition picture. Our first-principles calculations find little role of correlation. Our calculated reflectivity and conductivity data for both the high-temperature and low-temperature phases are found to be in good agreement with measured data by Wang et al. Phys. Rev. B 69 153104 (2004).